In his new book, climate scientist David Keith offers A Case for Climate Engineering. (I wrote a bit about solar radiation management recently.) He advocates spraying sulfate aerosols into the atmosphere where the particles would then reflect sunlight back into space. A bit less sunlight hitting the planet would help offset global warming from carbon emissions. Here is a bit from a Boston Review chat with Keith on how SRM pairs with reducing carbon emissions:
Geoengineering without emissions reductions just digs a deeper hole. Emissions reductions are a necessary part of any sensible climate policy.
It is possible to make big progress cutting emissions if we implement policies that include a significant price on carbon emissions and strong incentives for clean energy innovation. But while it is in our power to end the phony war on carbon and begin serious work to drive emissions toward zero, it would be extraordinarily hard to bring emissions near to zero in less than half a century, and even if we did, substantial climate risk would remain from the carbon that has accumulated in the atmosphere, carbon that will keep changing the climate for centuries to come.
Solar geoengineering provides a means—risky and uncertain—to limit climate change in the near term, risks that fall on vulnerable ecosystems and vulnerable human populations. But solar geoengineering can do nothing to limit the very long-term risks associated with carbon buildup in the atmosphere. Thus there is a sense in which emissions reductions and solar geoengineering are complementary.
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